This invention relates to pivot pins of the type used for mounting a bucket on a boom arm of a tractor loader and, more particularly, to a pivot pin assembly which can be installed without the use of shims while maintaining proper clearances thereby facilitating assembly and disassembly of the pivot joint.
Pivot pin assemblies which are utilized for pivotal attachment of a bucket to the boom arm of a loader are exposed to a very hostile environment due to the abrasive nature of materials being handled by the bucket and the close proximity of such assemblies to those materials. In addition, such pivot pin assemblies are subjected to severe loading as a result of manipulation of the bucket and the loader vehicle in order to fill the bucket with the material being handled and to then extricate the material from the bucket. This often requires the intentional imposition of shock loads in order to vibrate the bucket and dislodge any material adhering to it. Because of this, the sealing and lubrication requirements of such pin assemblies as well as maintaining the proper clearances between the parts become quite important. At the same time because these pin joints will have relatively high mortality compared to other portions of the loader, it is necessary to facilitate servicing of this joint.
In U.S. Pat. No. 4,251,182, I have disclosed a serviceable pivot pin assembly having a headed pin slideably fit in one bracket aperture, a thrust collar slideable on the other end of the pin, and a bolted-on end plate for locking the pin, thrust collar, and bucket bracket as a unit. However, to maintain proper side clearance for the bushings in the boom arm, it was necessary to install shims between the end plate and the pin. Although it did provide the benefit of complete and easy serviceability, there were too many loose parts involved.
In previous pin assemblies, such as shown in U.S. Pat. No. 3,997,274, wedging collets were employed. However, such collets make it very difficult to control the side clearance of the boom arm bushings unless the collars are welded to the pin. If the end collars are welded to the pin, as also shown in U.S. Pat. No. 4,096,957, the pin boom arm bushings and collars cannot be serviced separately.